package com.jtw.common.util;

import java.util.Date;

/* 安全散列算法SHA (Secure Hash Algorithm，SHA) */
public class SHA1 {

    private final int[] abcde = {0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476, 0xc3d2e1f0};

    // 摘要数据存储数组
    private int[] digestInt = new int[5];

    // 计算过程中的临时数据存储数组
    private int[] tmpData = new int[80];

    // 计算sha-1摘要
    private int process_input_bytes(byte[] bytedata) {
        // 初试化常量
        System.arraycopy(abcde, 0, digestInt, 0, abcde.length);
        // 格式化输入字节数组，补10及长度数据
        byte[] newbyte = byteArrayFormatData(bytedata);
        // 获取数据摘要计算的数据单元个数
        int MCount = newbyte.length / 64;
        // 循环对每个数据单元进行摘要计算
        for (int pos = 0; pos < MCount; pos++) {
            // 将每个单元的数据转换成16个整型数据，并保存到tmpData的前16个数组元素中
            for (int j = 0; j < 16; j++) {
                tmpData[j] = byteArrayToInt(newbyte, (pos * 64) + (j * 4));
            }
            //摘要计算函数
            encrypt();
        }
        return 20;

    }

    // 格式化输入字节数组格式
    private byte[] byteArrayFormatData(byte[] bytedata) {
        // 补0数量
        int zeros = 0;
        // 补位后总位数
        int size = 0;
        // 原始数据长度
        int n = bytedata.length;
        // 模64后的剩余位数
        int m = n % 64;
        // 计算添加0的个数以及添加10后的总长度
        if (m < 56) {
            zeros = 55 - m;
            size = n - m + 64;

        } else if (m == 56) {
            zeros = 63;
            size = n + 8 + 64;
        } else {
            zeros = 63 - m + 56;
            size = (n + 64) - m + 64;
        }

        // 补位后生成的新数组内容
        byte[] newbyte = new byte[size];
        // 复制数组的前面部分
        System.arraycopy(bytedata, 0, newbyte, 0, n);
        // 获得数组Append数据元素的位置
        int l = n;
        // 补1操作
        newbyte[l++] = (byte) 0x80;
        // 补0操作
        for (int i = 0; i < zeros; i++) {
            newbyte[l++] = (byte) 0x00;
        }
        // 计算数据长度，补数据长度位共8字节，长整型
        long N = (long) n * 8;

        byte h8 = (byte) (N & 0xFF);

        byte h7 = (byte) ((N >> 8) & 0xFF);

        byte h6 = (byte) ((N >> 16) & 0xFF);

        byte h5 = (byte) ((N >> 24) & 0xFF);

        byte h4 = (byte) ((N >> 32) & 0xFF);

        byte h3 = (byte) ((N >> 40) & 0xFF);

        byte h2 = (byte) ((N >> 48) & 0xFF);

        byte h1 = (byte) (N >> 56);

        newbyte[l++] = h1;

        newbyte[l++] = h2;

        newbyte[l++] = h3;

        newbyte[l++] = h4;

        newbyte[l++] = h5;

        newbyte[l++] = h6;

        newbyte[l++] = h7;

        newbyte[l++] = h8;

        return newbyte;

    }

    private int f1(int x, int y, int z) {

        return (x & y) | (~x & z);

    }

    private int f2(int x, int y, int z) {

        return x ^ y ^ z;

    }

    private int f3(int x, int y, int z) {

        return (x & y) | (x & z) | (y & z);

    }

    private int f4(int x, int y) {

        return (x << y) | x >>> (32 - y);

    }

    //单元摘要计算函数
    private void encrypt() {

        for (int i = 16; i <= 79; i++) {

            tmpData[i] = f4(tmpData[i - 3] ^ tmpData[i - 8] ^ tmpData[i - 14]

                    ^ tmpData[i - 16], 1);

        }

        int[] tmpabcde = new int[5];

        for (int i1 = 0; i1 < tmpabcde.length; i1++) {

            tmpabcde[i1] = digestInt[i1];

        }

        for (int j = 0; j <= 19; j++) {

            int tmp = f4(tmpabcde[0], 5)

                    + f1(tmpabcde[1], tmpabcde[2], tmpabcde[3]) + tmpabcde[4]

                    + tmpData[j] + 0x5a827999;

            tmpabcde[4] = tmpabcde[3];

            tmpabcde[3] = tmpabcde[2];

            tmpabcde[2] = f4(tmpabcde[1], 30);

            tmpabcde[1] = tmpabcde[0];

            tmpabcde[0] = tmp;

        }

        for (int k = 20; k <= 39; k++) {

            int tmp = f4(tmpabcde[0], 5)

                    + f2(tmpabcde[1], tmpabcde[2], tmpabcde[3]) + tmpabcde[4]

                    + tmpData[k] + 0x6ed9eba1;

            tmpabcde[4] = tmpabcde[3];

            tmpabcde[3] = tmpabcde[2];

            tmpabcde[2] = f4(tmpabcde[1], 30);

            tmpabcde[1] = tmpabcde[0];

            tmpabcde[0] = tmp;

        }

        for (int l = 40; l <= 59; l++) {

            int tmp = f4(tmpabcde[0], 5)

                    + f3(tmpabcde[1], tmpabcde[2], tmpabcde[3]) + tmpabcde[4]

                    + tmpData[l] + 0x8f1bbcdc;

            tmpabcde[4] = tmpabcde[3];

            tmpabcde[3] = tmpabcde[2];

            tmpabcde[2] = f4(tmpabcde[1], 30);

            tmpabcde[1] = tmpabcde[0];

            tmpabcde[0] = tmp;

        }

        for (int m = 60; m <= 79; m++) {

            int tmp = f4(tmpabcde[0], 5)

                    + f2(tmpabcde[1], tmpabcde[2], tmpabcde[3]) + tmpabcde[4]

                    + tmpData[m] + 0xca62c1d6;

            tmpabcde[4] = tmpabcde[3];

            tmpabcde[3] = tmpabcde[2];

            tmpabcde[2] = f4(tmpabcde[1], 30);

            tmpabcde[1] = tmpabcde[0];

            tmpabcde[0] = tmp;

        }

        for (int i2 = 0; i2 < tmpabcde.length; i2++) {

            digestInt[i2] = digestInt[i2] + tmpabcde[i2];

        }

        for (int n = 0; n < tmpData.length; n++) {

            tmpData[n] = 0;

        }

    }

    // 4字节数组转换为整数

    private int byteArrayToInt(byte[] bytedata, int i) {

        return ((bytedata[i] & 0xff) << 24) | ((bytedata[i + 1] & 0xff) << 16)

                | ((bytedata[i + 2] & 0xff) << 8) | (bytedata[i + 3] & 0xff);

    }

    // 整数转换为4字节数组

    private void intToByteArray(int intValue, byte[] byteData, int i) {

        byteData[i] = (byte) (intValue >>> 24);

        byteData[i + 1] = (byte) (intValue >>> 16);

        byteData[i + 2] = (byte) (intValue >>> 8);

        byteData[i + 3] = (byte) intValue;

    }

    // 将字节转换为十六进制字符串

    private static String byteToHexString(byte ib) {

        char[] Digit = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A',

                'B', 'C', 'D', 'E', 'F'};

        char[] ob = new char[2];

        ob[0] = Digit[(ib >>> 4) & 0X0F];

        ob[1] = Digit[ib & 0X0F];

        String s = new String(ob);

        return s;

    }

    // 将字节数组转换为十六进制字符串

    private static String byteArrayToHexString(byte[] bytearray) {

        String strDigest = "";

        for (int i = 0; i < bytearray.length; i++) {

            strDigest += byteToHexString(bytearray[i]);

        }

        return strDigest;

    }

    // 计算sha-1摘要，返回相应的字节数组

    public byte[] getDigestOfBytes(byte[] byteData) {

        process_input_bytes(byteData);

        byte[] digest = new byte[20];

        for (int i = 0; i < digestInt.length; i++) {

            intToByteArray(digestInt[i], digest, i * 4);

        }

        return digest;

    }

    // 计算sha-1摘要，返回相应的十六进制字符串

    public String getDigestOfString(byte[] byteData) {

        return byteArrayToHexString(getDigestOfBytes(byteData));

    }


    //测试

    public static void main(String[] args) {

        String appid = "xjmtuuz33ihofdva4duqya8m1jdebgclpcqegv60";
        String appsecret = "eltiyvnwosqzx5vnlifb4tz3d3zo7wimojaxhxrf";
        long timestamp = new Date().getTime();
        int nonce = 0;
        while (nonce < 100000) {
            nonce = (int) (Math.random() * 1000000);
        }
        System.out.println("加密前：" + appid + ":" + appsecret + ":" + timestamp + ":" + nonce);
        String checksum = new SHA1().getDigestOfString((appid + appsecret + timestamp + nonce).getBytes());
        System.out.println("加密后：" + checksum);

    }
}